The Korean-American chef wasn't afraid to start back at the bottom and climb her way to the top of another industry. She described squeezing lemons and picking through spinach for hours at a time.

"It's so much more rewarding. I'm creating memories, where as before I felt like I was just pushing paper around," Joo said.

But she still relies on her Wall Street savvy. Her financial background provided her with an important skill-set that translates to the culinary world. "I can actually model spreadsheets and do all my own forecasting, which is really helpful because most chefs can't do that," Joo said.

In 2015, the celebrity chef opened her first restaurant, Jinjuu, in London. She wanted to create a "cool" restaurant that borrowed from her Korean-American heritage. She now has a second location operating in Hong Kong.

"I need to create a space that is really representative of, and really shows off, the true beauty of Korean culture in every sense of the word," she said.

Popular menu items include Philly cheesesteak dumplings and wild mushrooms and duck dumplings. Joo is a French-trained Londoner, so she incorporates different robust flavors from her multicultural background.

"I am trying to globalize Korean food," she said.

Joo has made her footprint both on and off screen. She is the mastermind behind the cookbook "Korean Food Made Simple," and serves as a host of the Cooking Channel's "Korean Food Made Simple."